LT1129CST-3.3#PBF from Analog Devices, in a SOT-223-3. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	VIN	power_in	Input pin supplying power to the device; withstands reverse voltages (absolute maximum ±30V) and should be bypassed with 1μF to 10μF if more than 6 inches from the main input filter capacitor.
2	GND	power_in	Ground pin, also connected to the package tab (tab is GND).
3	OUTPUT	power_out	Regulated 3.3V output supplying up to 700mA to the load, which requires an output capacitor (stable with 3.3μF) to prevent oscillation.

Key specifications

Parameter	Value
Manufacturer	Analog Devices
Package	SOT-223-3
Category	Power Management ICs
Pins	3

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Regulated Output Voltage (LT1129-3.3), VIN = 3.8V, IOUT = 1mA, TJ = 25°C		3.25	3.3	3.35	V	VIN = 3.8V, IOUT = 1mA, TJ = 25°C	4
Regulated Output Voltage (LT1129-3.3), full range		3.2	3.3	3.4	V	4.3V < VIN < 20V, 1mA < IOUT < 700mA, l	4
Line Regulation (LT1129-3.3)			1.5	10	mV	ΔVIN = 4.8V to 20V, IOUT = 1mA, l	4
Load Regulation (LT1129-3.3), TJ = 25°C			6	15	mV	ΔILOAD = 1mA to 700mA, TJ = 25°C	4
Load Regulation (LT1129-3.3), full range			20	30	mV	ΔILOAD = 1mA to 700mA, l	4
Dropout Voltage at 10mA, TJ = 25°C			0.13	0.2	V	ILOAD = 10mA, TJ = 25°C	4
Dropout Voltage at 10mA, full range				0.25	V	ILOAD = 10mA, l	4
Dropout Voltage at 100mA, TJ = 25°C			0.25	0.35	V	ILOAD = 100mA, TJ = 25°C	4
Dropout Voltage at 100mA, full range				0.45	V	ILOAD = 100mA, l	4
Dropout Voltage at 500mA, TJ = 25°C			0.37	0.45	V	ILOAD = 500mA, TJ = 25°C	4
Dropout Voltage at 500mA, full range				0.6	V	ILOAD = 500mA, l	4
Dropout Voltage at 700mA, TJ = 25°C			0.45	0.55	V	ILOAD = 700mA, TJ = 25°C	4
Dropout Voltage at 700mA, full range				0.7	V	ILOAD = 700mA, l	4
Ground Pin Current at 0mA			50	70	μA	ILOAD = 0mA, l	4
Ground Pin Current at 10mA			310	450	μA	ILOAD = 10mA, l	4
Ground Pin Current at 100mA			2	3.5	mA	ILOAD = 100mA, l	4
Ground Pin Current at 300mA			10	20	mA	ILOAD = 300mA, l	4
Ground Pin Current at 500mA			25	45	mA	ILOAD = 500mA, l	4
Ground Pin Current at 700mA			50	90	mA	ILOAD = 700mA, l	4
Shutdown Threshold (Off to On)		1.2		2.8	V	VOUT = Off to On, l	4
Shutdown Threshold (On to Off)		0.25		0.75	V	VOUT = On to Off, l	4
Shutdown Pin Current			6	10	μA	VSHDN = 0V, l	4
Quiescent Current in Shutdown			15	25	μA	VIN = 6V, VSHDN = 0V, l	4
Ripple Rejection		52	64		dB	VIN, VOUT = 1V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 0.7A, TJ = 25°C	5
Current Limit		1.2	1.6		A	VIN, VOUT = 7V, TJ = 25°C	5
Input Reverse Leakage Current				1	mA	VIN = -20V, VOUT = 0V, l	5
Reverse Output Current (LT1129-3.3)			16	25	μA	VOUT = 3.3V, VIN = 0V	5
Input Voltage		-30		30	V	Input Voltage ±30V (contact factory for higher ratings)	2
Output Pin Reverse Current				10	mA		2
Sense Pin Current				10	mA		2
Adjust Pin Current				10	mA		2
Sense Pin, Adjust Pin Reverse Voltage		-0.6			V		2
Shutdown Pin Input Voltage		-0.6		6.5	V	Note 2	2
Shutdown Pin Input Current				20	mA	Note 2	2
Storage Temperature Range		-65		150	°C		2
Operating Junction Temperature Range (LT1129C-X)		0		125	°C	LT1129C-X	2
Thermal Resistance Junction-to-Ambient (ST package, 3-lead SOT-223)	θJA		50		°C/W	ST package, 3-lead SOT-223	2
Thermal Resistance Junction-to-Ambient, SOT-223 (topside copper 2500 sq. mm)			45		°C/W	Topside copper 2500 sq. mm, backside 2500 sq. mm, board 2500 sq. mm	11
Thermal Resistance Junction-to-Ambient, SOT-223 (topside copper 1000 sq. mm)			45		°C/W	Topside copper 1000 sq. mm, backside 2500 sq. mm, board 2500 sq. mm	11
Thermal Resistance Junction-to-Ambient, SOT-223 (topside copper 225 sq. mm)			53		°C/W	Topside copper 225 sq. mm, backside 2500 sq. mm, board 2500 sq. mm	11
Thermal Resistance Junction-to-Ambient, SOT-223 (topside copper 100 sq. mm)			59		°C/W	Topside copper 100 sq. mm, backside 2500 sq. mm, board 2500 sq. mm	11

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part	Material	Colour / plating	Datasheet says	Page
contacts	COPPER		Table 1. Q Package, 5-Lead DD COPPER AREA THERMAL RESISTANCE	11

CAD (KiCad official)

Symbol: LT1129CST-3.3#PBF
Footprint: Package_TO_SOT_SMD:SOT-223-3_TabPin2
3D model: SOT-223-3 (KiCad packages3D, STEP)
3D model files: lt1129cst-3-3-pbf-etched.step / lt1129cst-3-3-pbf-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lt1129cst-3-3-pbf.step / lt1129cst-3-3-pbf.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Analog Devices datasheet (16 pp, sha256 3bd8354699849a4f, retrieved 2026-10-31, tier: manufacturer)
Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF

LT1129CST-3.3#PBF

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3D Model

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